In the field of liquid crystal display technology, an Advanced Super Dimension Switching (AD-SDS or ADS) type array substrate is widely used as it has advantages of a wide viewing angle, etc. ADS technology is to generate a multi-dimensional electric field with both an electric field produced at edges of slit electrodes in the same plane and an electric field produced between a slit electrode layer and a plate-shaped electrode layer, so that liquid crystal molecules at all directions, which are located directly over the electrodes and between the slit electrodes in a liquid crystal cell, can be rotated, which enhances the work efficiency of liquid crystals and increases light transmittance. The ADS technology can improve the picture quality of thin film transistor liquid crystal displays (TFT-LCDs) and has advantages of high resolution, high transmittance, low power consumption, wide viewing angle, high aperture ratio, low chromatic aberration, being free of push Mura, etc.
In conventional technology, ADS type array substrate comprises a plurality of pixel units, as shown in FIGS. 1 and 2, in each of the pixel units, a glass substrate 09 is fabricated with a gate line 05 made of gate material, over which a gate insulation layer 03 is deposited, an active layer 07 of a predetermined pattern is disposed over the gate insulation layer 03, and a source/drain electrode metal layer, which is used for fabricating a source electrode 08 and a drain electrode 010 of a predetermined pattern, is provided over the active layer 07; a first transparent conductive layer, which is used for fabricating a pixel electrode 01 (i.e. a plate-shaped electrode), is disposed over the above source /drain electrode metal layer, a passivation layer 04 is deposited over the first transparent conductive layer, and a second transparent conductive layer for fabricating common electrodes 02 (i.e. slit electrode) is disposed over the passivation layer 04, wherein a plurality of slits are formed between the common electrodes 02.
A LCD panel has a plurality of pixel units in an imaging region of the LCD panel, and the pixel electrode 01 located in display region of each pixel unit is covered by a multilayer structure subsequently fabricated, and thus it is impossible to make a detection for TFT semiconductor characteristics prior to cutting the substrate. Therefore, in conventional technology, a liquid crystal panel is provided with dedicated detection modules at edges of the whole liquid crystal panel (i.e., non-display region) for the sake of detecting. These detection modules are fabricated together with the respective layers in the display region, but the modules only have the pixel electrode layer and the layers beneath, while the multilayer structures over the pixel electrode are not fabricated, so the pixel electrode of these detection modules may be detected by means of a detecting device. Both the pixel electrode of the detection modules and the pixel electrode of the pixel units are supplied with the same parameters during the detection, such as voltage, current, etc. The semiconductor characteristics of the pixel electrode in other pixel units can be deduced by detecting the semiconductor characteristics of the pixel electrode of detection modules.
However, due to the resistance difference between the detection modules and each the pixel unit, the detection result obtained by detecting the pixel electrode of detection modules are much different from the actual characteristics of the pixel electrode of each pixel unit, which is detrimental to an in-depth analysis and investigation of the TFT, and even sometimes it is impossible to exactly know how would be the actual work situation of the designed TFT, which resulting in a potential risk of great uncertainty .
Therefore, a technical problem to be solved by one skilled in the art is how to provide an array substrate so as to improve the detection accuracy for the pixel electrode in each individual pixel unit.